Apollo-17月海玄武岩样品的仪器和放射化学多元素中子活化分析
MULTIELEMENTAL NEUTRON ACTIVATION ANALYSIS OF AN APOLLO-17 LUNAR MARE BASALT SAMPLE USING INSTRUMENTAL AND RADIOCHEMICAL METHODS
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摘要: 本文利用仪器和放射化学组分离的方法,在62.10mg Apollo-17月海玄武岩样品中,测定了36种元素的含量。仪器中子活化分析共测定了Al,V,Ti,Ca,Dy,Mn,Eu。Na,Sm,La,Ho,Lu,Yb,Tb,Hf,Cr,Fe,Co,Sc等19种元素。用42.10mg样品,在堆中子通量为2×10~(13)n/cm~2·s处辐照40h。冷却12h后,用混合酸溶解样品,通过HAP-717树脂组成的串联柱,再用TTA和铜铁试剂—氯仿萃取,最后通过50%和10%的HDEHP萃取色谱柱,将36种元素分成12组,又测定了Pr,Er,Gd,Nd,Ce,Tm,Cs,Rb,Sb,Zn,Zr,Sr,Ba,Ga、Ta,U和Th等17种元素。γ能谱的测量和数据处理是在具有高效率(30%)、高分辨率(1.9keV)Ge(Li)探测器的SCORPIO—3000系统上进行的。我们的测定结果,对主量和微量元素,尤其是镧系元素的含量与报道的Apollo—17月海玄武岩数值范围相符合。Abstract: By means of instrumental and radiochemical methods, 36 elements are determined in an Apollo-17 lunar mare basalt sample. Total amount of the sample is only 62.10 mg. By using instrumental neutron activation analysis, 19 elements (Al, V, Ti, Ca, Dy, Mo, Eu, Na, Sm, La, Ho, Lu, Yb, Tb, Hf, Cr, Fe, Co, and Sc) are determined for one part of the sample (20.00mg). The other part of the sample (42.10 mg) is irradiated at a thermal flux of 2×1013 n/cm2. s for 40 h. After 12 h cooling, radiochemical separation is preformed and 17 more elements (Pr, Er, Gd, Nd, Ce, Tm, Cs, Rb, Sb, Zn, Zr, Sr, Ba, Ga, Ta, U and Th) are determined. The separation procedure consist of ion exchange, solvent extraction and reverse phase chromatography, resulting in the separation of 36 elements into 12 groups. A CANBERRA SCORPIO-3000 system is used for γ-ray spectrum measurements and data processing. The system includes a Ge (Li) detector with an energetic resolution of 1.9 keV and a relative efficiency of 30% and a computerized data acquisition and reduction system. For each element determined, two or more comparative standards are independently prepared to ensure the reliability of the standards. Accuracy of the results is verified by parallel analysis of USGS SRM W-1 sample. Most of the experimental results including ' 14 rare earth elements agree quite well with those reported in the literature for Apollo-17 lunar mare basalt samples.